Retrievable well packer apparatus

ABSTRACT

In accordance with an illustrative embodiment of the present invention, a retrievable well packer apparatus includes a mandrel adapted for connection to a pipe string and carrying normally retracted slips that can be expanded into anchoring engagement with a well casing; a slip expander assembly on the mandrel below the slips and movable upwardly to expand the slips, and instrumentalities responsive to rotation of the mandrel by the pipe string for mechanically retracting the slips so that the slips cannot be accidentally set as the packer is being withdrawn from a well.

Umted States Patent 1 1111 3,744,563

McGill [45] July 10, 1973 l RETRIEVABLE WELL PACKER 3,516,493 6/1970MCGlll .Q. 166/140 APPARATUS 3,695,352 10/1972 McGill 166/139 XInventor: Howard L. McGill, 5434 Carew, Houston, Tex. 77035 Filed: 061.26, 1972 Appl. N6: 300,927

Related US. Application Data Division of Ser. No. 174,598, Aug. 25,1971.

us. (:1 166 139, 166/140, 166/134 1111. c1 E216 23/06, 12216 33/128Field 61 Search ..l66/l38-l40, 134, 216, 217

References Cited UNITED STATES PATENTS 8/1955 "Brown 166/140X PrimaryExaminer pavid H. Brown I Attorney-Ernest R. Archambeau, Jr., David L.Moseley et a1.

[57] ABSTRACT ln accordance with an illustrative embodiment of thepresent invention, a retrievable well packer apparatus includes amandrel adapted for connection to a pipe string and carrying normallyretracted slips that can be expanded into anchoring engagement with awell casing; a slip expander assembly on the mandrel below the slips andmovable upwardly to expand the slips, and instrumentalities responsiveto rotation of the mandrel by the pipe string for mechanicallyretracting the slips so that the slips cannot be accidentally set as thepacker is being withdrawn from a well.

3 Claims, 8 Drawing Figures PAIENIED JUL 1 0 ma FIG. 18

ngmgu JUL 1 mars 55 saw a or 3 V RETRIEVABLE WELL PACKER APPARATUS Thisapplication is a division of application Ser. No. 174,598, filed Aug.25, 1971.

This invention relates generally to well packers used in well bores, andmore specifically to a well packer apparatus having new and improvedmeans for preventing inadvertent setting of the packer as it is beingretrieved to the surface after use.

Retrievable well packers commonly used for isolating well bore zones aregenerally lowered into the well bore on a running-in string of tubing ordrill pipe. The packer has normally retracted slips which can beexpanded into engagement with the well casing to anchor the tool at apreselected depth, as well as expansible packing that functions whenexpanded to seal off the annulus between the pipe string and thesurrounding well conduit wall. When it is desired to retrieve the tool,both the slips and the packing can be retracted to positions enablingfree running in the well bore.

It is highly undesirable for the slips or the packing to he accidentallyoperated while the tool is being moved through the well casing becausethis may result in damage to the tool or to the well casing or both.Particularly when retrieving the tool, such premature operation may alsoresult in damage to the running-in string which is being pulled intension at the surface. In any event, it is desirable to have provisionfor disarming the well packer so that it is not possible to accidentallyoperate the slips or the packing as the tool is being withdrawn from thewell casing.

It is the principal object of the present invention to provide a new andimproved retrievable well packer apparatus having means for positivelypreventing accidental operation of the tool as it is being retrieved tothe surface.

This and other objects are. attained in accordance with the concepts ofthe present invention through the provision of a wellpacker apparatusincluding a body member which is adapted to be secured to a running-instring and to be moved by the string in a well bore. The body membercarries normally retracted slips which can be shifted outwardly intogripping contact with the well bore wall by upper and lower expanderswhich are movable longitudinally on the body member and rela-,

tive to the slip means for shifting the slip means outwardly. The upperexpander has a slidable spline connection to the slips. A lug sleevethreadedly secured to the mandrel has lugs that engage in a channelsystem formed in a control sleeve that is rigidly attached to the upperexpander. The lug sleeve occupies one position on the mandrel duringlowering and cooperates with the channel sytem to prevent setting untilsuch time as the mandrel is appropriately manipulated to enable suchsetting; When it is desired to retrieve the well packer to the surface,with the slips set the mandrel can be rotated to cause the lug sleeve tofeed upwardly to another position along the mandrel where outwardlydirected shoulders thereon engage downwardly facing shoulders on thecontrol sleeve. Further rotation causes the control sleeve and upperexpander to move relatively upwardly along the mandrel to effect amechanical retraction of the slips. When mechanical retraction hasoccurred, it is impossible to set the slips during upward movement sothat the packer is completely disarmed and can be retrieved to thesurface without accidental setting.

in conjunction with the accompanying drawings in which:

FIGS. IA and 1B are longitudinal sectional views, with portions in sideelevation, of .a well packer apparatus in accordance with thisinvention, FIG. 18 forming a lower continuation of FIG. 1A;

FIG. 2 is a cross-section on line 22 of FIG. 1A;

FIG. 3 is a schematic plan view of a channel configuration which is usedto enable selective control over relative movement between parts;

FIG. 4 is a cross-section taken on line of FIG. 1A;

FIGS. 5A and 5B are longitudinal sectional views similar to FIGS. 1A and1B, except with the parts of the packer shown in the relative positionsthey occupy when the packer is set in a well casing; and

FIG. 6 is a view similar to FIG. 1A except showing the slips inmechanically retracted condition.

Referring initially to FIGS. 1A and 18, a well packer constructed inaccordance with the principles of the present invention includes atubular body member or mandrel 10 having a central passage 11 throughwhich fluid can flow. A threaded collar 12 is provided at the upper endof the mandrel l0 and is adapted to couple the mandrel to the lower endof a running-in string of drill pipe or tubing 13. The mandrel 10carries, from top to bottom, an upper drag assembly 15 that is coupledby a control sleeve 16 to an upper expander 17 which is movablerelatively toward a lower expander 18 in order to expand normallyretracted slips 19 into gripping contact with the well casing. The lowerexpander 18 is secured to the upper end of a lower drag assembly 20. Apacking structure 21 has normally retracted elements 22 which whenexpanded seal off the cross sectional area of the well bore between themandrel l0 and the surrounding well casing wall. The slips 19 functionto prevent longitudinal movement in either direction in the well casing,and the packing 21 prevents fluid flow in either longitudinal directionpast its sealing point, so that the well zone below the packer isisolated from the well fluids thereabove.

The upper drag assembly 15 includes an annular cage member 24 having agauge ring 25 secured by bolts or the like to its upper end. The cagemember 24 has a plurality of radially directed, circumferentially spacedrecesses 26, each of which receives a drag block 27. Each drag block 27is urged outwardly by springs 28 having one end engaged within a recess29 in the drag block and the other end pressing against the back surfaceof a respective recess. Stop shoulders 30 at each end of each drag block27 limit outward movement thereof with respect to the cage member 24.The control sleeve 16 is threadedly secured to the lower end of the cagemember 24 by an annular cap 32, and the lower end of the control sleeve16 is threadedly secured to the upper expander 17. Formed through thewall of the control sleeve 16 at diagonally opposed positions is achannel configuration 33 shown in plan view in FIG. 3. Each channel hasa transverse pocket 34 in its lower end that is connected by a shortvertical portion 35 to an intermediate transverse portion 36. Theportion 36 connects with a lengthy vertical portion 37. The generallystepped formation of the channel 33 provides two circumferentiallyspaced, axially facing shoulders 38 and 39. Each channel is adapted toreceive a lug 40 formed by an outwardly directed shoulder on a lugsleeve 41 that is secured to the mandrel 10 by companion jack threads 42and 43. As shown in FIG. 1A, the lug sleeve 41 normally occupies a lowerposition on the mandrel l and is made up tightly at the lower endportion of the threads 42. If desired, a compression coil spring 44 canbe positioned between the lower end of the lug sleeve 41 and anoutwardly directed shoulder 45 on the mandrel in order to provide anaxial load on the threads and thereby inhibit turning motion of the lugsleeve in response to low torque values. As shown in FIG. 2, twodiametrically opposed lugs 40 are used although it will be appreciatedthat at least one is required and that more than two can be used. Anouter barrier sleeve 46 can be positioned over the control sleeve 16 toprevent entry of particles of foreign matter that may be in the wellfluids into the channels 33.

The slip assembly 19 is constituted by a plurality of circumferentiallyspaced individual slip elements 50 that are slidably coupled to theupper expander 17 and are mounted on the mandrel 10 for bothlongitudinal and lateral movement relative thereto. Each slip element 50has peripheral wickers or teeth 51 which can bite into and grip the wellcasing in order to prevent movement in either direction therein, andalso has upper and lower inclined surfaces 52 and 53 that are adpated toslidably engage companion inclined surfaces 54 and 55 on the upper andlower expanders 17 and 18, respectively. The slip elements 50 aremounted on a ring member 54 which is relatively slidable on the mandrel10 below an annular stop shoulder 55. The ring member 54 can be anintegral piece as shown in cross-section in FIG. 4, or can be formed insegments secured together by threaded studs. In any event, the ringmember 54 has circumferentially spaced, radially directed recesses 56,each of which receives a central portion 57 of a respective slip elementto provide a lateral guide therefor. As previously noted, the ringmember 54 can slide downwardly relative to the mandrel 10, howeverupward movement is limited by the downwardly facing stop shoulder 55.Each slip element 50 is coupled to the upper expander 17 through a dovetail sliding connection that can be formed, for example, by keys 58 thatare suitably secured to the upper expander 17 by studs, each keyslidably fitting within a slot 59 in a respective one of the slipelements.

The lower drag assembly 20 is formed by a cage member 61 having aplurality of circumferentially disposed, radially extending recesses 62,each of which receives a drag block 63. The drag blocks are urgedoutwardly by coil springs 64 in the same manner as discussed above withrespect to the upper drag assembly 15. Upward movement of the lower dragassembly 20 is limited by engagement between an upwardly facing shoulder65 on a gauge ring 66 that is attached to the lower end of the cagemember with a downwardly facing shoulder 67 formed by an annularenlargement on the mandrel 10.

The packing structure 21 includes an annular compression sleeve 70 whichis threaded to the upper end ofa bottom sub 71 which is in turnthreadedly fixed to the lower end of the mandrel 10. The compressionsleeve 70 carries the annular packing elements 22 constructed of asuitable elastomeric material. The lower packing ring is engaged by anupwardly facing lower abutment 72, whereas the upper ring is engaged bya downwardly facing upper abutment 73 which is slidable relatively alongthe compression sleeve 70. The upper abutment 73 is secured to a splinecollar 74 having an inwardly thickened piston section 75 at its upperend which is sealed with respect to the mandrel 10 by an O- ring 76 orthe like. The upper abutment 73 is also sealed with respect to thecompression sleeve 70 through use of an O-ring 77. The inner wallsurface of the compression sleeve 70 is spaced laterally with respect tothe outer wall surface of the mandrel 10 to provide a fluid passagespace 78 in communication with the well annulus below the packing by oneor more ports 79 through the wall of the bottom sub 71. Thus, it will beappreciated that the pressure of fluids in the well bore below thepacking is communicated by the ports 79 and the annular passage space 78into a chamber 80 located interiorly of the spline collar 74 forpurposes to be more fully described hereafter.

To prevent relative rotation between various parts of the packer, theupper end portion of the compression sleeve 70 has splines 82 whichslidably engage in companion spline grooves 83 formed in the collar 74.Moreover, the upper end of the spline collar 74 is provided with aplurality of upwardly extending clutch pins 84 which engage like clutchpins 85 on the lower end of the gauge ring 66 when the parts areslidably disposed in engagement with each other. In engaged condition,the spline collar 74 cannot rotate with respect to the compressionsleeve 70, nor can the lower drag assembly 20 rotate with respect to thespline collar 74.

In operation of the structure described above, it will be apparent thatthe assembled tool can be connected to the lower end of the pipe string13 and pushed downwardly along the well casing to setting depth asadditional joints of pipe string are added in end-to-end relation. Thelower drag blocks 63 slide along the well casing, and the coengagedshoulders 65 and 67 on the mandrel 10 and the cage member 61 maintainthe lower expander 18 in spaced relation to the slip elements 50. Theupper drag blocks 27 are also sliding along the casing wall as thedownward movement of the mandrel 10 is being transmitted thereto byengagement of the lugs 40 in the lower transverse pockets 34 of thechannels 33. The slip elements 50 are being held in retracted positionsby their sliding connection with the upper expander 17, together withengagement of the mounting ring 54 underneath the mandrel shoulder 55.Of course, the packing rings 22 are in their inherently retractedpositions so that well fluids can pass between the rings in the wellcasing wall.

When it is desired to set the packer, the tool is halted and right-handtorque coupled with an upward strain applied to the pipe string 13 willposition the lugs 40 within the elongated vertical portions 37 of thechannels 33. As previously described, the drag blocks 27 function toprevent movement of the upper cage member 24, the control sleeve 16 andthe upper expander 17. As the mandrel 10 is pulled upwardly, the packingstructure 21 is elevated until the upper end of the spline collar 74engages the lower end of the lower drag assembly 20, whereupon thepacking structure and the lower expander 18 are jointly elevated towardthe slip elements 50. This results in outward shifting of the slipelements 50 until their teeth 51 bite into and grip the well casingwall. Then the upper abutment 73 cannot move any further upwardly,whereby continued upward movement of the mandrel 10 telescopes thecompression sleeve 70 upwardly within the upper abutment 73 and effectscompression and lateral expansion of the packing rings 22 until theirouter peripheries seal against the well casing wall. A predeterminedamount of upward strain is maintained on the pipe string 13 at theearths surface in order to maintain the tool in set condition within thecasing 88 as shown in FIGS. 5A and 58.

It should be specifically noted at this point that both of the expandermembers 17 and 18 are engaging the slip elements 50. This engagedrelation will be maintained during the operation of the packer and untilit is desired to release the tool for retrieval from the well. With theslip elements 50 set and the packing elements 22 expanded, the well borebelow the tool can be pressurized as desired and the slip elements willprevent upward movement while the packing rings seal off the wellannulus.

Should a sufficiently high pressure exist in the annulus above thepacker,.the packing structure 21 and the mandrel can shift downwardly toa limited extent in the casing, such limited shifting being accompaniedby stretching of the pipe string. However, the slip elements 50 remainin anchoring position and engaged by both expander members 17 and 18.Downward movement of the mandrel 10 will bring the lugs 40 against theshoulder surfaces 38, whereupon downward force on the mandrel. 10 isimposed by the upper expander member 17 on the slip elements 50 whichprevent further downward movement.

During this movement, the packing rings 22 merely slide downwardly alongthe casing 88 in expanded condition and remain sealed there against.This will occur because thelesser fluid pressure is acting on the lowerface 89 of the piston section 75, while the greater pressure is actingon theupper face 90 thereof, the pressure differential acts on thepiston area as downward force which is applied to the upper end of thepacking rings 22 by the upper abutment 73. It will be remembered thatupward strain is still being exerted on the pipe string 13 so thatcompressive force is being applied continuously to the lower end of thepacking rings by the lower abutment 72. Accordingly, since compressiveforce is being exerted on both ends of the packing rings 22, they willnot retract but will slide downwardly along thecasing wall in expandedand sealing condition. The actual extent of downward shifting of themandrel 10 and the packing assembly 21 is actually quite short comparedto prior art devices of this general type, and may be only two or threeinches. I

If the pressure in the annulus above the packer is reduced, of coursetension is still being held on the pipe string 13 and the string cancontract and shift the packing assembly 21 and the mandrel 10 backupwardly to their original position with the upper and lower expanders17 and 18 cooperating with the slip elements 50 to prevent furtherupward movement. In fact as long as tension is held on the pipe string13, the packing structure 21 and the mandrel 10 can shift back and forthand it will be appreciated that the well bore remain sealed off toprevent any fluild movement past the tool. Moreover, the slip elements50 remain anchored against the well casing wall and remain supported inanchored position by both the upper and lower expander members insimultaneous engagement therewith.

To unset the tool, pressures above and below the packer are equalized byoperation of a suitable bypass valve (not shown) as upward strain on thepipe string 13 is relieved and as the mandrel 10 is moved downwardly bylowering the pipe string. This relieves the compressive force on thepacking rings 22 so that they can inherently retract. The mandrelshoulder 67 will engage the cage shoulder 65 to push the lower expander18 out from behind the slip elements 50. The lugs 40 are manipulatedback into the lower transverse pockets 34 of the channels 33 to lock theupper expander l7 and the upper drag assembly 15 in their upperpositions on the mandrel 10. Then an upward pull on the pipe string 13will lift the upper expander 17 and cause the slips 50 to shift inwardlyalong the inclined surfaces of the expander to their retractedpositions,

whereupon the tool is free to be moved upwardly or downwardly within thecasing 88.

As previously discussed, it is often times desirable to be able tosafety the tool during removal thereof from the well. In other words,some operators may desire to completely disarm the tool immediatelybefore retrieving it so that it is impossible to again set the slips andthe packing in the well bore. One typical circumstance where this isparticularly desirable is where the pipe string is rotated out of thehole. This is a procedure wherein the rotary table is used to break andback off pipe joints at the surface. Since the pipe is being rotated asubstantial number of turns to the right (the direction that is normallyused to condition the tool for setting) there would normally be asubstantial risk to accidental setting. To prevent accidental setting inaccordance with the principles of the present invention the structurepreviously described can be operated as follows. With the slips 50 setagainst the casing, a certain amount of weight, for example, 3,000-5,000lbs., is slacked off onto the tool and the pipe string 13 is rotated tothe right. With the tool set the lugs 40 are in the elongated portions37 of the channels 33 shown in FIG. 3. Since the upper drag assembly 15and the temporarily set condition of the slips 50 prevents rotation ofthe control sleeve 16 within the casing, rotation of the mandrel 10 willcause the lugs sleeve 41 to feed relatively upwardly along the mandrel10 until the upper end surface 92 thereof comes against the downwardlyfacing shoulder 93 provided by the lower end of the cage member 24. Whenthis has occurred, further rotation moves the lugs sleeve 41 upwardlyand the mandrel l0 downwardly with corresponding movement of expander 17and the slips 50. Since the slips can move upwardly only as limited bythe shoulder 55, the dove tail connections 58, 59 effect a retraction ofthe slips as shown in FIG. 6. Actually the ships 50 are onlyset for abrief period of time for the purpose of preventing rotation ofthe upperexpander 117 (since these two members have a spline connection), duringwhich time a fairly high torque may be applied to the threadedconnection 42, 43 between the lug sleeve 40 and the mandrel 10 toinitiate upward feeding of the lug sleeve along the mandrel. Once thelug sleeve 40 starts its upward travel along the mandrel 10 however, thetorque requirements are substantially lessened and the lug sleeve willfeed freely along the mandrel until it comes into engagement with theshoulder 93 and causes the control sleeve 16 to move upwardly, drawingthe upper expander 17 upwardly therewith. With the slips 50 mechanicallyretracted as discussed above, the tool cannot again be set on this tripinto the well and the operator can pull the tool from the well as fastas he desires, and can rotate the pipe string 13 freely, without fearthat the tool will, by some fortuitous circumstance, accidentally hangup and set in the casing.

in accordance with an additional safety feature, the thread 95 whichjoins the bottom sub 71 to the lower end of the mandrel 10 can be formedon a left-hand helix. It is thus possible to manipulate the packer aspreviously discussed in order to effect a setting thereof with the pipestring in tension, and then rotate the pipe string to the right. Sincethe compression sleeve 70 and the spline collar 74 are corotativelycoupled, as are the spline collar 74 and the lower drag assembly 20, theslips 50 serve to frictionally hold the various members against rotationin the casing 88, and the right-hand rotation will effect unthreading ofthe thread 95 between the mandrel and the bottom sub. When suchunthreading has occurred, it is possible to remove the mandrel 10 andall parts of the well packer above the lower expander member 18 from thewell, leaving the balance of the parts behind for subsequent retrievalby a fishing operation with typical equipment.

it will be appreciated that the entire tool shown in the drawings couldbe inverted or turned upside down and then run into the well bore, inwhich case the tool could be set in compression by pipe weight ifdesired. Also, of course the rotational directions for setting andunsetting movement applied to the pipe string at the suface are afunction of the configuration of the slot system, which can be arrangedfor right-hand or left-hand torque as desired.

It will now be apparent that the present invention provides a new andimproved retrievable well packer apparatus which can be set in packedoff condition against longitudinal movement in a well bore, and includesstructure for disarming the slips so that it is impossible to set theslips and the packing during retrieval of the packer from the well bore.Since certain changes or modifications may be made by those skilled inthe art without departing from the inventive concepts involved, it isthe aim of the appended claims to cover all such changes ormodifications falling within the true spirit and scope of the presentinvention.

I claim:

LA well packer apparatus comprising: a body member adapted forconnection to a pipe string; normally retracted slip means on said bodymember arranged to be expanded into anchoring engagement with a wellcasing wall; upper expander means above said slip means and lowerexpander means below said slip means, said lower expander means beingmovable upwardly by said body member relatively toward said upperexpander means and said slip means to expand said slip means; normallyretracted packing means on said body member below said lower expandermeans and adapted to be compressed and expanded by movement of said bodymember upwardly relative to said slip means and said lower expandermeans; means providing a slidable spline connection between said slipmeans and said upper expander means; means for limiting upward movementof said slip means along said body member; and safetying meansresponsive to rotation of said body member for causing said slidablespline connection to effect a mechanical retraction of said slip meansand to a condition such that said lower expander cannot contact saidslip means during upward movement in a well bore.

2. The well packer apparatus of claim 1 wherein said safetying meansincludes a sleeve structure connected to said upper expander means, dragmeans to inhibit rotation of said sleeve structure in a well bore, andcontrol means having threaded connection to said body member andoutwardly directed shoulder extending into a channel means in saidsleeve structure, rotation of said body member relative to said controlmeans and said sleeve structure causing said control means to feedupwardly along said body member until said outwardly directed shouldercontacts an inwardly directed shoulder on said sleeve structure,whereupon continued rotation will feed said sleeve structure upwardlyrelative to said slip means to cause said slidable spline connection toretract said slip means.

3. The well packer apparatus of claim 2 wherein said channel meansextends generally longitudinally of said sleeve structure and includes atransverse portion adapted to receive said outwardly directed shoulderduring downward movement of said apparatus in a well bore.

1. A well packer apparatus comprising: a body member adapted forconnection to a pipe string; normally retracted slip means on said bodymember arranged to be expanded into anchoring engagement with a wellcasing wall; upper expander means above said slip means and lowerexpander means below said slip means, said lower expander means beingmovable upwardly by said body member relatively toward said upperexpander means and said slip means to expand said slip means; normallyretracted packing means on said body member below said lower expandermeans and adapted to be compressed and expanded by movement of said bodymember upwardly relative to said slip means and said lower expandermeans; means providing a slidable spline connection between said slipmeans and said upper expander means; means for limiting upward movementof said slip means along said body member; and safetying meansresponsive to rotation of said body member for causing said slidablespline connection to effect a mechanical retraction of said slip meansand to a condition such that said lower expander cannot contact saidslip means during upward movement in a well bore.
 2. The well packerapparatus of claim 1 wherein said safetying means includes a sleevestructure connected to said upper expander means, drag means to inhibitrotation of said sleeve structure in a well bore, and control meanshaving threaded connection to said body member and outwardly directedshoulder extending into a channel means in said sleeve structure,rotation of said body member relative to said control means and saidsleeve structure causing said control means to feed upwardly along saidbody member until said outwardly directed shoulder contacts an inwardlydirected shoulder on said sleeve structure, whereupon continued rotationwill feed said sleeve structure upwardly relative to said slip means tocause said slidable spline connection to retract said slip means.
 3. Thewell packer apparatus of claim 2 wherein said channel means extendsgenerally longitudinally of said sleeve structure and includes atransverse portion adapted to receive said outwardly directed shoulderduring downward movement of said apparatus in a well bore.